THERMOELECTRIC-POWER STUDY ON HIGH-T-C BI-2212 AND BI-2223 OXIDES INTERCALATED WITH ORGANIC-MOLECULES ZINCPHTHALOCYANINE

We have systematically studied the behavior of the thermoelectric powe r S for the high-T-c Bi-2212 and -2223 oxides intercalated with organi c molecules zincphthalocyanine (ZnPc). The intercalating level x range s from zero to 0.02 per formula, while T-c is degraded from 110 to 85 K for (ZnPc)(n)Bi-2223 and from 90 to 61 K for (ZnPc)(x)Bi-2212. It ha s been observed that the value of S at T = 290 K, S(290), increases wi th increasing x for both systems. Based on an empirical rule, the carr ier concentration n is extracted from S(290). It has been found that n drops sharply for x changing from zero to 0.005, and then decreases g radually with increasing x for both the (ZnPc)(x)Bi-2212 and -2223 sys tems, The relation of n with x resembles that of T-c with x. Our resul ts suggest that the charge transfer between the ZnPc molecules and the CuO2 layers plays an important role in the T-c-suppression by the ZnP c intercalation. The T-c/T-c0-n relations for these samples fall on th e same curve, in contrast with the previously reported results, This s caling behavior is consistent with the universality of the T-c/T-c0-n relation which was proposed previously by Zhang and Sate.